1. Field of the Invention
The present invention relates to a capacitance sensing apparatus and method, and a touch screen apparatus.
2. Description of the Related Art
A touch sensing apparatus such as a touch screen, a touch pad, or the like, an input apparatus integrated with a display apparatus to provide an intuitive input method to a user, has recently been widely used in various electronic apparatuses such as a portable phone, a personal digital assistant (PDA), a navigation device, or the like. Particularly, as demand for smart phones has grown in recent times, the use of a touch screen as a touch sensing apparatus capable of providing various input methods in a limited form factor has correspondingly increased.
Touch screens used in portable apparatuses may be largely classified as resistive-type touch screens and capacitive-type touch screens according to a method of sensing a touch input utilized therein. Here, capacitive-type touch screens have advantages in that they have a relatively long lifespan and various input methods and gestures may be used therewith, such that the use thereof has increased. Particularly, a multi-touch interface may more easily be implemented in capacitive-type touch screens as compared to resistive-type touch screens, such that a multi-touch interface is widely used in smart phones, and the like.
Capacitive-type touch screens include a plurality of electrodes having a predetermined pattern defining a plurality of nodes in which a change in capacitance is generated by a touch input. In the plurality of nodes distributed on a two-dimensional plane, a change in self-capacitance or a change in mutual-capacitance is generated by the touch input. Coordinates of the touch input may be calculated by applying a weighted average method, or the like, to the change in capacitance generated in the plurality of nodes. In order to accurately calculate the coordinates of the touch input, a technology capable of accurately sensing the change in capacitance generated by the touch input is required. However, in the case in which electrical noise is generated in a wireless communications module, a display apparatus, or the like, it may hinder the change in capacitance from being accurately sensed.